With sposies, we have 4 heavy ones in the day (1-2 have poo too), and overnight one is normally about a third full. For the longest use, it has the least amount of wee. When she was younger she wee'd heaps, the night nappy was like 1kg in the morning. Toddlers drink more and therefore wee more. Every bub is different though. Maybe try a cover and boosters with sposies for heavy wetters.